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Snow Goose
Snow geese are known for their white plumage, but many of them are actually darker, gray-brown birds known as blue geese. These birds were once though to be two separate species, but they have recently been found to be merely two different color morphs of the same bird. A single gene controls the color difference. Migration and Diet Snow geese are harbingers of the changing seasons. They fly south for the winter in huge, honking flocks that may appear as a "V" formation or simply as a large "snowstorm" of white birds. They spend the colder seasons in southern coastal marshes, bays, wet grasslands, and fields. Their diet is entirely vegetarian, consisting of grasses and grains, grazed from damp soils or even shallow water. Reproduction At winter's end, snow geese fly north to their breeding grounds on the Arctic tundra. Pairs mate for life, and produce two to six eggs each year in a shallow ground nest. Chicks can swim and eat on their own within 24 hours, but families remain together through the young's first winter. Families can be identified as groups during both the southern and northern migrations. Population Decline and Rebound In 1916, snow geese had become so rare in the eastern United States that hunting of the species was banned. Since that time, the birds have made a remarkable comeback. Today, though hunting has been reinstated, populations are thriving. In fact, the birds have become so numerous in places that they threaten to destroy their own habitat. Ecology Outside of the nesting season, they usually feed in flocks. In winter, snow geese feed on left-over grain in fields. They migrate in large flocks, often visiting traditional stopover habitats in spectacular numbers. Snow geese frequently travel and feed alongside greater white-fronted goose; in contrast, the two tend to avoid travelling and feeding alongside Canada geese, which are often heavier birds. The population of greater snow geese was in decline at the beginning of the 20th century, but has now recovered to sustainable levels. Snow geese in North America have increased to the point where the tundra breeding areas in the Arctic and the saltmarsh wintering grounds are both becoming severely degraded,9 and this affects other species using the same habitat. Major nest predators include Arctic foxes and skuas. The biggest threat occurs during the first couple of weeks after the eggs are laid and then after hatching. The eggs and young chicks are vulnerable to these predators, but adults are generally safe. They have been seen nesting near snowy owl nests, which is likely a solution to predation. Their nesting success was much lower when snowy owls were absent, leading scientists to believe that the owls, since they are predatory, were capable of keeping competing predators away from the nests. A similar association as with the owls has been noted between geese and rough-legged hawk. Additional predators at the nest have reportedly included wolves, coyotes and all three North American bear species. Few predators regularly prey on snow geese outside of the nesting season, but bald eagles (as well as possibly golden eagles) will readily attack wintering geese. Category:Birds Category:Geese Category:Waterfowl Category:North American Animals